The present invention relates to a semiconductor device and method of manufacturing the same, to a circuit board and to an electronic instrument.
In recent years, with the increasing compactness of electronic instruments, the development of multichip modules incorporating a plurality of semiconductor chips at high density is proceeding. With a multichip module, since an existing plurality of semiconductor chips can be used, the cost can be reduced compared with the design of a new integrated circuit.
However, conventional multichip modules have used wire bonding to connect interconnect pattern of a substrate to the electrodes of the semiconductor chip. As a result, the interconnect pattern requires bonding pads for the wires, and therefore the area of the substrate is increased, preventing the required compactness of the package from being fully achieved.
The present invention solves this problems, and has as its object the provision of a compact semiconductor device incorporating a plurality of semiconductor chips at high density and a method of manufacturing the same, of a circuit board and of an electronic instrument.
(1) A semiconductor device of the present invention comprises:
a plurality of semiconductor chips having electrodes, and aligned in a horizontal direction for face-down bonding;
a substrate on which an interconnect pattern is formed, the interconnect pattern having bonding portions to which the electrodes of the semiconductor chip are connected, and lands to which the bonding portions are electrically connected; and
external electrodes provided on the lands.
According to this aspect of the present invention, a plurality of semiconductor chips is aligned in a horizontal direction and mounted on a substrate. Each semiconductor chip is subjected to face-down bonding. Since the bonding is carried out within the region where the semiconductor chip is mounted, the area of the substrate can be kept to the minimum required. As a result, the semiconductor device can be made more compact.
(2) In the semiconductor device:
the external electrodes may be disposed within mounting regions of the semiconductor chips.
By means of this, external electrodes can be provided corresponding to the electrodes of the semiconductor chip, within the region where each semiconductor chip is mounted.
(3) In the semiconductor device:
the external electrodes may be disposed outside regions where the semiconductor chips are mounted.
By means of this, the external electrodes can be aligned on the periphery of the substrate.
(4) In the semiconductor device:
the substrate may be a flexible substrate and is formed to be larger than the regions where the semiconductor chips are mounted, and a flat support member may be provided on a periphery of the substrate.
By means of this, even if a flexible substrate is used, the uniform height (coplanarity) of the external electrodes can be assured by means of the flat support member.
(5) In the semiconductor device:
the external electrodes may be disposed within a region where any one of the semiconductor chips is mounted.
By means of this, all of the external electrodes can be provided within the region where any one of the semiconductor chips is mounted, and no external electrodes can be provided within the region where any other semiconductor chip is mounted.
(6) In the semiconductor device:
the substrate may be a flexible substrate and part of the substrate is bent; and
a surface of the one semiconductor chip, which is disposed at a region where the external electrodes are provided, opposite to a surface on which the electrodes are formed may be adhered to a surface of at least one remaining semiconductor chip opposite to a surface on which the electrodes are formed.
Since on the semiconductor chip another semiconductor chip is adhered, the size of the semiconductor device in the horizontal direction can be reduced.
(7) In the semiconductor device:
the substrate may have at least one hole formed along a region to be bent.
By forming the hole in the substrate, the resilience of the substrate can be reduced, and the bent state can be more easily maintained.
(8) In the semiconductor device:
the hole may be a slot extending along a bending line;
the interconnect pattern may be formed to pass over the hole; and
an edge of the slot extending along the bending line may form a part of an outer edge.
Since a part of the outer edge of the semiconductor device is formed by an edge of the slot, the edge of the semiconductor device can be positioned accurately.
(9) In the semiconductor device:
a plurality of the holes may be formed;
the interconnect pattern may be formed to pass over the plurality of holes; and
the plurality of holes may be slots extending along a bending line, and are aligned.
By means of this, the substrate may be made easier to bend. (10) In the semiconductor device:
the substrate may have a slit formed along a region to be bent; and
the substrate may be divided by the slit, and a gap may be opened up between opposing divided edges.
When the divided substrate is considered as a whole, it can be bent more easily.
(11) In the semiconductor device:
a joining member may be provided spanning the slit.
By means of this, the bent portion of the substrate can be supported by the joining member.
(12) In the semiconductor device:
a flexible resin may be provided on the interconnect pattern in the hole; and
the resin may be bent together with the substrate.
By means of this, the bent portion of the substrate can be supported by the resin.
(13) In the semiconductor device:
the semiconductor chips may be adhered by an electrically conductive adhesive or a thermally conductive adhesive.
When an electrically conductive adhesive is used, the electrical potential of the adhering surfaces of the semiconductor chips can be made the same. When a thermally conductive adhesive is used, cooling can be achieved by passing heat from the semiconductor chip which emits more heat to the semiconductor chip which emits less heat.
(14) In the semiconductor device:
a surface area of one of the semiconductor chips may be larger than a surface area of a remaining semiconductor chip; and
the external electrodes may be formed only in a region where the semiconductor chip having a larger surface area is provided.
By means of this, the largest possible region for providing the external electrodes can be assured, without going outside the surface area of the semiconductor chip.
(15) In the semiconductor device:
the electrodes of the semiconductor chips may be connected to the bonding portions by an anisotropically conductive material including conductive particles dispersed in an adhesive.
Since the bonding portions and electrodes are electrically connected by the anisotropically conductive material, a semiconductor device can be manufactured by a method of outstanding reliability and productivity.
(16) A method of manufacturing a semiconductor device of the present invention comprises:
a step of providing a substrate on which an interconnect pattern is formed, the interconnect pattern having a plurality of bonding portions and a plurality of lands electrically connected to the bonding portions, and providing a plurality of semiconductor chips having electrodes;
a step of providing anisotropically conductive materials including conductive particles dispersed in an adhesive at least on the bonding portions;
a step of positioning the electrodes over the bonding portions on the anisotropically conductive materials, and mounting the semiconductor chips over the substrate;
a step of applying pressure to at least one of the semiconductor chips and the substrate so that the bonding portions and the electrodes are electrically connected by the conductive particles; and
a step of forming external electrodes on the lands.
According to this aspect of the present invention, a plurality of semiconductor chips is mounted on the substrate, and the electrodes of the semiconductor chips and bonding portions are subjected to face-down bonding. Therefore, since the bonding is carried out within the region where the semiconductor chip is mounted, the area of the substrate can be kept to the minimum required. As a result, the semiconductor device can be made more compact.
Since the bonding portions and electrodes are electrically connected by the anisotropically conductive material, a semiconductor device can be manufactured by a method of outstanding reliability and productivity.
(17) In this method,
the substrate may be a flexible substrate and formed to be larger than the regions where the semiconductor chips are mounted; and
a flat support member may be provided on a periphery of the substrate.
By means of this, even if a flexible substrate is used, the uniform height (coplanarity) of the external electrodes can be assured. In the case where all of the external electrodes are provided outside the region where all of the semiconductor chips are mounted, the external electrodes can be provided on the region to which the flat support member is attached.
(18) The method may further comprise a step of bending a part of the substrate, after the step of mounting the semiconductor chips on the substrate, so that a surface of one of the semiconductor chips opposite to a surface where the electrodes are provided is adhered to a surface of another of the semiconductor chips opposite to a surface on which the electrodes are formed.
Since on the semiconductor chip another semiconductor chip is adhered, the size of the semiconductor device in the horizontal direction can be reduced.
(19) In this method,
the substrate may have at least one hole formed along a region to be bent.
In this way, by forming a hole in the substrate, the resilience of the substrate can be reduced, and the substrate can be made easier to bend.
(20) The circuit board of the present invention has the above described semiconductor device mounted.
(21) The electronic instrument of the present invention has the above described circuit board.